The Administrative and Biostatistics Core will provide the overall leadership as well as the infrastructure for the Program Project Grant (PPG). The four Projects in the PPG represent independent but highly interactive proposals by experienced investigators who have a long track record of collaborative studies. A major goal of the Core, therefore, is to ensure optimal interaction and integration among the Projects. These diverse Projects also need the appropriate infrastructure and logistical support, such as sample acquisition and storage, data management, and central administrative coordination. Finally, throughout the history of this PPG, the Core has provided statistical support to the investigators and trainees associated with the Projects. This is the only Core being requested in support of this PPG, owing in large part to the unique environment at Mayo, where institutional Cores provide much of the needed scientific infrastructure. Thus, the Specific Aims for the Core are 1) To provide the administrative leadership for the PPG; 2) To provide the appropriate infrastructure for the conduct of the studies; and 3) To provide the biostatistical resources needed for the design and analysis of the studies. Aim 1 is accomplished through an internal Administrative Committee that will meet on a regular basis as well as an external Advisory Committee that will meet by teleconference every six months. Aim 2 is accomplished by a dedicated sample processing and data management team, along with administrative support. Aim 3 relies on the expertise of Dr. Therneau, Ms. Atkinson (a Masters level statistician who has had a long-term participation in the PPG), and a data analyst. These individuals accomplish complex statistical functions and also provide statistical advice and support to each of the investigators. Collectively, the Administrative and Biostatistics Core is the underpinning of this highly successful endeavor. This is reflected, in part, by the unique ability of our group to combine knowledge gained from population-based epidemiology studies, intensive human investigation, animal studies, and basic bone biology. Moreover, the success of the infrastructure and biostatistical support is perhaps best reflected by the ongoing productivity of our group, thus making the sum clearly greater than the parts.